Automatic train-control system



Nov. 25, 19%. 1,5172% W. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM Original Filed May 15 1919 Patented Nov. 25, TORT.

WINTHRO'P K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEW YORK, A CORPORATION OF NEW YORK.

AUTOMATIC TRAIN-CONTROL SYSTEM.

Original application filed May 15, 1919, Serial No. 2973 13, now Patent No. 1,510,496, dated October 7, 1924. Divided and this application filed January at, 1923. Serial No. 614L592.

To all whom it may concern:

Be it known that I, W INTHFROI K. Howe, a citizen of the United States of America, residing at Rochester, in the county of Monltroe and State of New York, have invented certain new and useful Improvements in Automatic Train-Control Systems, of which the following is a specification.

This invention relates to train control W systems for railroads.

Tn automatic train control systems, it is essential to communicate from the track to the moving train some sort of a control impulse or influence under unsafe traiiic con- 11% ditions in order to accomplish the desired control of the train movement. On account of the clearance problems, weather conditions, and other limitations existing in practice, it is considered desirable to communicate such control influences inductively through an intervening air gap and without physical contact between car-carried parts and trackway parts.

One of the principal objects of the present invention is to provide a simple and effective means for communicating a stopping influence from the track to the moving train inductively, subject to control to conform with traflic conditions, in conformity with the well-known and dependable principles of electromagnetic induction. Various specific objects and characteristic features of the invention will appear hereinafter.

The subject matter of this application is divided from my Mprior application Serial No. 297 ,343, filed ay 15, 1919, now Patent No. 1,510,496, dated October 7, 1924.

In the accompanying drawings, Figure 1 shows one construction and arrangement of trackway circuits embodying the invention; and

Fig. 2 illustrates in a simplified and diagrammatic manner the track element and the car equipment of the invention in their superimposed or cooperating relation.

In the accompanying drawings, have illustrated my system applied to only two blocks; but it will be readily recognized by those skilled in the art that in practice the same scheme and arrangement of parts would be associated with the several blocks to constitute a complete system as required, and with such variations as special conditions may demand. The various devices commonly used in ordinary block signaling are shown in a conventional manner; and since the various relays, contacts, and the like, associated with the various blocks, are the same, these devices and parts thereof Will be given the same reference characters, with distinctive exponents added.

Referring to Fig. 1, the track rails 1 and 2 of the railroad track are divided into blocks by insulating joints 3 in the usual and well known manner, the length of these blocks being, of course, selected to conform with the braking distances of the trains traveling over the track. Each of these blocks is provided with the usual and well known normally closed track circuit, comprising a track battery 4: and a track relay 5. The usual fixed signals S, ordinarily employed in block signal systems, are shown conventionally; and for simplicity, the controlling circuits for these signals have not been shown.

Associated with each block is a trackway element T, the function of which is to transmit controlling impulses to assing trains, depending upon trailic con itions in the next block in advance. The trackway element T illustrated is of the inductive type, and comprises (see Fig. 2) two side members 6-6, shown as angular in cross-section, which extend along the track parallel with the track rails 1 and 2 for a distance suitable for obtaining the desired duration of impulse; a cross-connecting core 7; and a coil 8 on said core. In accordance with this invention, it is contemplated that the trackway element T will cooperate with a car-carried element and associated control devices. of the type requiring the coil 8 of the trackway element T to be energized for clear trafic conditions, and to be deenergized under dangerous trafiic conditions.

Referring to Fig. 1, the energizing circuit for the coil 8 of the trackway element T may be traced as follows: commencing at one terminal of the coil 8, conductor 9, back contact of track relay 5, conductor 10, front contact of line relay L, conductor 11, track battery 12, conductor 13 and back to the other terminal of said coil. As the train enters each block, it shunts out the track relay 5 of that block, and if the next block Kat in advance is not occupied, the front 'contact of the line relay L is closed, so that the circuit for energizin (mil 8 of the trackway element in question is established. In this arrangement, the trackway element T of each block is located in advance of the insulating joints 3 at the entrance to that block and at a distance therefrom sufficient to permit the shunting of the track rela 5 and the complete energization of the Coll 8 before a train traveling at maximum s reaches the trackway element T. It will be observed that the circuit for energizing the trackway element is normally open and is closed only upon the approach of a train, and that it is again opened as soon as the train has passed out of the block. In this way, there is no current demand upon the track battery 12 except when required; and since this occurs at comparatively infreuent intervals during the passage of trains, t e primary batmries, ordinarily employed in block signal systems, may be utilized for supplying current to the trackway elements of the train control system.

Referring to Fig. 2, the car carried element L comprises a magnetic yoke Y having pole pieces 22. Coils 23 are carried on each leg of the yoke Y, and are connected in series with the battery 24, a check relay 25 and the primary of a transformer 26. The secondary of said transformer 26- is connected in circuit with the windings of a control relay R, preferably of a type responsive to alternating currents. The train control asparatus governed by the check relay 25 an the control relay B may be of any suitable construction, and is shown diagram matically as an electro-pneumatic "alve E. V. adapted to cause an automatic application of the brakes, or control some other suitable means. The circuit for the E. P. V. includes a battery 27 the back contact of a contact finger or; arma ture 28 of the control relay R, and the front contact and armature 29 of the check relay 25.

While the car or train is travelin between signaling points, the current from the battery 24 passes through the coils 23 and magnetizes the yoke Y with a polarity, such as indicated in Fi 2. Under clear traffic conditions, the coi 8 of the trackway element T is energized from the track battery 12, as previously explained; and the arrangement is such that the side members 66 of said trackwav element have a polarity, as indlcated in Fig. 2, opposing the polarity of the pole pieces of the oke Y on assing cars. Consequently, un er clear tra 0 conditions, when the car passes a trackway element, the reluctance of the magnetic circuit through the yoke Y is not materially altered, at least not enough to cause operation of the relay R. Under dangerous trafic conditions, however, the coil 8- of the trackway element T is open-circuited, so that said trackway element presents in effect a magnetic bridge or loop for the yoke Y on a passing car. Thus, the reluctance of the magnetic circuit through the yoke Y on the passing car is greatly changed, thereby resulting in changing the amount of magnetizing current flowing through the coils 23 and through the primary of the transformer 26. This change in current in the primary of the transformer 26 induces a current in its secondary, thereby picking up the control relay R and deenergizing the E. P. V. or other train control device. The check relay 25 assures the integrity of the circuit for energizing the coils 23; and if this circuit should become broken. or the battery 24 depreciate, the check relay 25 would cease to hold up its armature 29 and would interrupt the circuit for the E. P. V., thus producing an automatic operation of the E. P. V., or other train control device. to signify that the system is out of order. The transformer 26 and the-relay R are preferably constructed in a self-contained unit, all of the parts being of a substantial and sturdy construction such that no breaking or failure of parts is likely to occur.

In disclosing my invention, simplified and diagrammatic forms of illustration have been employed, and no attempt has been made to show the exact construction preferably employed in practice. Obviously various modifications may be made in the constructon illustrated, and other parts and devices may be added in order to make a more complete system, all without departing from my invention. I desire to have it understood, therefore, that the specific embodiments shown and described are merely illustrative of my invention, and do not exhaust the various modifications and adaptations 0f the underlying idea of means constituting my invention.

What I claim as new and desire to secure by Letters Patent, is

1. In an automatic train control system, a car-carried element adapted to be influenced inductively by a trackway element and including a magnetic yoke and coils; a circuit for energizing said coils including a battery, a check relay, and the primary of a transformer, a control relay connected in circuit with the secondary of said transformer; and automatic train control means governed jointly by said check relay and said control relay.

2. In a train control system, a car-carried influence receiving element comprising a magnetic core and a winding tl1ereon,acircuit including said Winding and a battery for normally producing a unidirectional current in said circuit, a transformer having its primary connected in said circuit, a

control relay connected to the secondary of said transformer, and brake control means governed by said control relay.

3. In a train control system, a brake control device, a relay responsive only to alternating currentand governing the operation of said device, a transformer having av secondary connected to said relay, a car element comprising a magnetic core and a winding thereon, a circuit energized with uni-directional current and including said winding and the primary of said transformer, and trackway means for varying the reluctance of the magnetic circuit through said core under dangerous traihc conditions.

4. Car equipment for automatic train control systems comprising, a car-carried element including colls and adapted to be influenced by electromagnetic induction from the trackway, an electro-responsive device operable only by alternating current, a governing circuit including the coils of the car element and inductively c0nnected to the electro-responsive device, and a separate check relay in said governing circuit operable upon interruption of said circuit.

5. In a train control system, a brake control device, a relay responsive only to alternating current and adapted when energized to cause operation of the brake control device, a U-shaped magnetic core carried on the car, coils on the legs of said core, a circuit including said coils and a source of direct current, means inductively coupling said circuit and said relay, and a track element acting under dangerous traffic conditions to complete the partial magnetic circuit through the car-carried core as the car passes over said track element.

6. In a train control system, the combination with a track element constituting an inert magnetic body when in the active stopping condition and an electro-magnet when in the inactive condition and car-carried means having a partial magnetic circuit and responding to changes in the reluctance of such circuit produced by the passage over the track element in its active stopping conresponsive to alternating currents only and inductively coupled to said circuit, train control means governed by the relay, and a track element disposed to complete the partial magnetic circuit through the carcarried core, said track element constituting an inert magnetic body when in the active stopping condition and when in the inactive condition being an electro-magnet having a-magnetic polarity opposite to that of the car-carried core.

In testimony whereof I hereby aflix my signature.

WINTHROP K. HOWE. 

